In recent years, as a representative of multicarrier modulation techniques (that is, multiplexing techniques or multiple access technologies), orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA) have been put to practical use in various wireless systems. Application examples include digital broadcasting, a wireless LAN, and a cellular system. OFDM has resistance with respect to a multipath propagation path and can prevent the occurrence of inter-symbol interference caused by a multipath delay wave by employing a cyclic prefix (CP). On the other hand, OFDM has a disadvantage in that a level of out-of-band radiation is large. Further, a peak-to-average power ratio (PAPR) tends to increase, and there is also a disadvantage in which it is vulnerable to distortion occurring in transmission and reception apparatuses.
New modulation techniques capable of suppressing such out-of-band radiation which is a disadvantage of OFDM are emerging. These modulation techniques introduce a new concept called a subsymbol and can design a time and a frequency of a symbol flexibly by dividing one symbol into an arbitrary number of subsymbols. Further, these modulation techniques can reduce unnecessary out-of-band signal radiation by applying a pulse shaping filter to a symbol and performing waveform shaping, and the frequency use efficiency is expected to be improved. Further, the present modulation technology makes it possible to more flexibly set a resource by introducing a subsymbol, and thus serves as a means for expressing diversity that is going to be desired in the future.
These modulation techniques have various names such as universal filtered-OFDM (UF-OFDM), universal filtered multi-carrier (UFMC), filter bank multi-carrier (FBMC), and generalized OFDM (GOFDM). Particularly, since these modulation techniques can be regarded as generalized OFDM, they are also referred to as generalized frequency division multiplexing (GFDM), and this name is employed in this specification. A basic technology related to GFDM is disclosed, for example, in Patent Literature 1 and Non-Patent Literature 1.